Did KoKo talk when she communicated her tooth ache by sign 
language? I would say yes.
http://en.wikipedia.org/wiki/Koko_(gorilla)

Do meerkats engage in service exchange?
http://nationalzoo.si.edu/Publications/ZooGoer/2007/1/meerkats.cfm
Trickier, but I would again say yes.

It has always fascinated me that so many economists wish
desperately to see humans as non-animals.  This may well
explain some failures to understand human behavior.
http://www.bushorchimp.com/pics.html

Alan Isaac

PS None of this is meant to deny that the human ability to 
handle abstraction (a *quantitative* difference, which 
varies substantially among humans) has had qualitative 
implications.